This invention relates, in general, to hybrids, and more specifically, to multi-phase broadband MMIC hybrids.
Broadband hybrids are basic building blocks for many analog microwave circuits. Until recently, most hybrids have been constructed for use at low frequencies. For low frequencies, hybrids have been constructed with ferrite materials which resulted in adequate power performances. However, advances in technology opened the way for greater use of circuits operating in the high frequency ranges. At microwave frequencies, hybrids have generally been constructed in distributed fashion, such as coupling two transmission lines together, or using multiple methods of construction such as are used in Large couplers. Unfortunately, such hybrids are not suitable for monolithic microwave integrated circuits (MMIC).
MMIC circuits are best suited to lumped element components due to the small available circuit area. Some MMIC hybrids have implemented lumped elements, but these MMIC hybrids have very narrow bandwidths. For instance, U.S. Pat. No. 4,893,098 issued Jan. 9, 1990 to the same inventors, and having the same assignee, as the present invention, incorporates lumped elements, but is limited to a bandwidth of less than an octave.